Gareth Edwards' 2010 debut feature Monsters was nothing short of a low-budget miracle. Shot for next to nothing, it still offered science fiction spectacle but only after investing in a richly detailed world of alien invaders and focussing intently on its human drama. If that was the equivalent of Ridley Scott’s Alien, then Monsters: Dark Continent would seem to be its bigger, bloodier, far more action packed sequel Aliens. This time, it really is war.

Monsters: Dark Continent expands Edwards' universe, so memorably envisioned in the first film. Upping sticks from Mexico to the Middle East, it follows a platoon of American soldiers, first as they prepare to be shipped off from Detroit, and then into the sweaty Infected Zone a million miles from home. These young men are mostly fresh from training, ready for their first tour and spoiling for a fight. Beset on all sides by the monstrous squid-like aliens and the hostile locals who also see them as invaders, the soldiers are soon way out of their depth.

Led on a rescue mission straight into the warzone by their hardened leader Frater (Johnny Harris), young soldier Michael Parkes (Keeley) and his friends are quickly outnumbered and many are blown to pieces. The remaining men’s survival will depend on each other but with so many monsters around (both human and alien); their journey to safety will be fraught with danger.

Make no mistake, Monsters: Dark Continent is barely science fiction. Its monsters are mostly of a far more human and recognisable kind. This is a world familiar from the contemporary war film; of checkpoints manned by jumpy Americans in desert fatigues, of buildings billowing smoke after relentless air strikes, and of IED's blowing soldiers to shreds. The aliens are jarring when they appear in the realistically designed world, like the prawns of District 9 but often far more towering and even majestic.

It's a ‘man on a mission’ movie, introducing its grunts back home before slamming them into the conflict. At first they are all bravado, bravery and bullshit. Leaving their families, wives, girlfriends, and babies behind, it’s soon time for shock and awe as the boys quickly get the fight they have been waiting for, and more. Even though these dumb kids may be asking for trouble, it is also clear that they have become soldiers out of a lack of choices. Like the human enemies they come across on the ground, they feel forced to fight. As Parkes says in his opening voiceover: it's either shift rubble, sell crack, or sign up.

By the time Monsters: Dark Continent gets into its visceral battle scenes, there is plenty of time to sympathise with its soldiers, even if some are the very monsters of the title. Johnny Harris is phenomenal as the leader of the group, a man so conflicted and so entrenched in modern warfare, that he has forgotten why he got there. When he screams 'Why am I here?' to anyone and no one in particular, it’s one of the most heart-wrenching moments in any film that has tackled the ongoing wars in the Middle East.

Director Tom Green gives every frame a heightened sun streaked Instagram effect with the visuals burning off the screen. The tense exchanges between untrusting characters demonstrate the difficulty of winning hearts and minds with guns in hands, but also offer emotional scenes of quiet hope. While its running time could have been trimmed slightly, Monsters: Dark Continent is thought provoking stuff. More Deer Hunter than Aliens, this is a heartfelt, angry film about the tragedy of ongoing modern warfare.

Although Sam Keeley is excellent in the starring role, it’s the soulful, mesmerising performance of Johnny Harris that really stands out. Hardcore sci-fi fans may still want more from the alien monsters but this Dark Continent is packed with intense action and plenty of subtext beneath its awe-inspiring spectacle.